Note: Neutral Grounded to Cabinet

[peterh770]

When you open up a dryer to connect a proper, new 30 amp power cable (3 prong) and you see a note next to the connection point that says neutral is grounded to the cabinet, along with a cable from the central neutral point to the block, is this something that should be changed, or do you just need to make sure the cabinet is properly grounded?

 

[peterh770]

Pic of the situation...

 

[Unimatic1140]

Peter the white wire from the neutral post to the screw on the terminal block is the ground wire. All that sticker is saying is to be sure to keep that wire installed or otherwise properly ground the cabinet to the neutral post (center post of the three screws).

 

[toggleswitch]

What exists in your machine is simply grounding through the

A proper new 30a cable................

Actually, the law (in the United States) now requires a 4-prong, 4-cable dryer outlet and cord in NEW installations (homes).

The old way... a three-prong, three-conductor cord may still be used when such an outlet (i.e. with only three "holes") is already exisitng.

If you were to upgade your receptacle (female) to the new 4- conductor, 4-prong, 4-hole style outlet, then:

#1= hot (black or red)
#2= neutral (white)
#3= hot (The OTHER hot. i.e. if black is on "1", then red)
#4= Screw to chassis/cabiet. New 4th green/ground wire from flexible connector/cord would go here.

Loop between 4th screw for ground and neutral terminal "#2" would be removed.

It is my understanding that in Canada 3-wire connections of electric (220v) clothes dryers with a shared neutral /ground is not permitted and has not been so since 1966, if ever. I remember this from installation instructions that came with my mother's Maytag dryer of that vintage.

 

[peterh770]

Thanks for the help! New pics coming soon...

 

[3beltwesty]

Here my 1976 Westinghouse Dryer is wired just like yours and has a 3 prong plug in an early 1970's house.

The dryer of mine like many of that era too can be wired for 120 volts too. Thus the motor runs on 120 volts neutral to one 120 volt hot leg; and the heater coil goes across both 120 volt legs; ie 240 volts. The patent plate on mine mentions using it on 240 volts; 208 volts in Y and just 120 volts too. For 208 volts both hot legs are 120 volts to neutral; but it is only 208 line to line. There are amperage ratings for each service; something roughly 12, 20 and 23 amps. The replacement heater coil kit on a Westinghouse/Frigidaire has the coil as is for 255 volts. Yes 255 volts; a rather weird voltage. One cuts the coil so many inches for 240, and some more for 208 volts *IF* one wants the full 5400 watts.

For the stock dryer set up for 120 volts; there is roughly 1/4 the wattage; ie about say 1400 watts because coil is not so red.

Before about say 1947 a new house's wiring could be just for 110 volts service. After WW2 AC units in houses and electric dryers added to a houses demands and the electrical code went to a minimum of about 60 amps at 220 volts; then 100 amp service became more of the norm say about 1960. Today the code requires a 200 amp service with todays bigger houses.

When I grew up the Westinghouse dryer was from the 1940's, and it was only a 110 volt unit. Its output was like a hair dryer today. Thus one used clothes line for bulky stuff.

A 3 prong unit normally is quite safe. If you add a 4 prong plug with a real green wire ground then you can upgrade the settup. Folks do this were there is liability, laundrymats, damp areas; dolts and fools. A 4th prong has to have a good ground. In my house like most the Neutral and ground anyway are tied together at the service panel. In the USA if one runs a sub panel away from the main entrance; then there is a real separate set of ground lugs too. With the sub panel 50 feet away and some unbalanced loads; the neutral will be a few volts from ground.

To have a failure with a 3 prong unit would have to have the neutral wander way above ground and have leakage to the frame; thus it is now real hot electrically. On your dryer; if the neutral is broken the AC motor stops.Probably then the heater would cause the thermal high switch to trip.

With an old 3 prong set up like mine and yours; another failure mode is where some Yoyo's like after Katrina where stealing scrap metal. They were stealing ones copper pipes in ones house that was gutted; stealing the copper ground wire on the outside breaker box, stealing the copper HVAC lines to ones outside AC units. Thus one had a house with an ungrounded service panel; a salt flooded house, and the electric company restoring power all over the place. In this case the neutral is still grounded back at the transformer/pole; but some looters clipped off these copper wires too.

Having your own known good green wire ground can help under weird conditions. The last thing you want is leakage to float a chassis above ground; thus the old way is to at least tie it to the neutral.

After Katrina and power was still flakey; the neutral came off at the pole and the 120 volt legs became imbalanced. one leg went to about 160 volts the other down to 80 volts. It blew up the garage down closer; a TV; a few light bulbs.